Effect of Netting Duration on Ethiopian Pepper Mottle Virus

Vol 2 | Issue 1 | Pages 6-12 Journal of Plant Pathology Research

Original Article DOI: 10.36959/394/619 Effect of Netting Duration on Ethiopian Pepper Mottle Virus (EPMV) Infection and Aphid Infestation of Hot Pepper (Capsicum annuum L.) in Central Rift Valley Region of Ethiopia Kumsa Dida1*, Alemayehu Chala2 and Ferdu Azerefegne2

1College of Agriculture and Natural Resource Management, Jinka University, Ethiopia 2College of Agriculture, Hawassa University, Ethiopia

Abstract Ethiopian pepper mottle virus is one of the major constraints of pepper production in the central rift valley region of Ethiopia. The present study was conducted to determine optimum netting duration for efficient protection of pepper from vector infestation and subsequent viral infection. For this purpose, an experiment was carried out in the central rift valley of Ethiopia (i.e. Meki and Hawassa districts). Data were collected on the number of aphid populations, virus incidence, and pepper growth parameters and yield. Significant variations at (p < 0.01) were observed between treatments of the field experiments in terms of aphid infestation, virus incidence and pepper yield. Covering of plots with net for up to 60 or more days after transplanting reduced aphids’ population per plant by a greater margin (61.8%-76.9% in Hawassa, 52.4-67% in Meki) and virus incidence by 48%-60.8% in Hawassa and 38.6%-48.5% in Meki as compared to the control plots. Total and marketable yields were significantly higher in plots protected by net for up to 60 days or more after transplanting while unmarketable yields were low in those plots. Low virus incidence and aphids’ population in plots covered by net up to 60 days after transplanting and longer resulted in increased yields by 44%-55% in Hawassa and 38%- 49.5% in Meki as compared to the control plots. Unmarketable yield was positively correlated (p < 0.001) with aphids population and virus incidence while total and marketable yields were negatively correlated with aphids population and virus incidence. The results suggest the need to apply control measures at early growth stages to effectively protect pepper plants from aphids and associated viruses. Keywords Aphid, Ethiopiapepper mottle virus, Netting duration Abbreviations EPMV: Ethiopian pepper mottle virus; GLM: General Linear Model; YWT: Yellow Water Traps; DAT: Days after transplanting; CMV: Cucumber Mosaic virus

Introduction cantly from one region to other region due to several factors such as topography, lack of improved varieties, soil type, wa- Hot pepper (Capsicums spp.) is one of the main crops be- longing to the family Solanaceae and used as fresh, dried or processed products, as vegetables and spices or condiments *Corresponding author: Kumsa Dida, College of Agriculture and grown in different parts of the world[1] . The genus Capsicum Natural Resource Management, Jinka University, P.O. Box 165, is the second main vegetable crop of the family after tomato Jinka, Ethiopia Solanaceae in the world [2]. Accepted: September 14, 2020 Hot pepper serves as one of the important sources of food Published online: September 16, 2020 and income to smallholder farmers and as exchange earning commodities [3]. It is important part in the daily diet of most Citation: Dida K, Chala A, Azerefegne F (2020) Effect of Netting Ethiopian societies. The standard daily utilization of hot pep- Duration on Ethiopian Pepper Mottle Virus (EPMV) Infection and Aphid Infestation of Hot Pepper (Capsicum annuum L.) in per by Ethiopian adult is estimated at 15 g, which is higher Central Rift Valley Region of Ethiopia. J Plant Pathol Res 2(1):6- than most other vegetables [4]. Pepper yields varies signifi- 12

Copyright: © 2020 Dida K, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and SCHOLARS.DIRECT reproduction in any medium, provided the original author and source are credited.

Open Access | Page 6 | Citation: Dida K, Chala A, Azerefegne F (2020) Effect of Netting Duration on Ethiopian Pepper Mottle Virus (EPMV) Infection and Aphid Infestation of Hot Pepper (Capsicum annuum L.) in Central Rift Valley Region of Ethiopia. J Plant Pathol Res 2(1):6-12 ter quality, drought, insect pest, diseases, different cultural plant viruses. For example, netting of okra plants for up to 4-5 practices, soil tillage and fertilizer application [5]. weeks reduced the number of jassids and whiteflies as well as virus infection when compared with that of un-netted plants Arthropod pests and diseases caused by different fungi, [13]. Therefore, the experiment was under taken to deter- bacteria and viruses are the most important ones [6]. Viral mine the optimum netting duration for efficient protection of diseases such as EPMV, potyvirus and fungal diseases like hot pepper from aphid’s infestation and EPMV infection and powdery mildew, stem and leaf blight, pod bleaching, damp- to evaluate the effect of EPMV on the yield of hot pepper un- ing off and bacterial leaf spot have emerged as severe threats der different netting durations. to the crop in the foremost producing areas [7,8]. Viruses are reported to cause total crop failure in addition to lowering Material and Methods yields and reducing fruit quality [6]. Site description More than 90% viral disease incidences and absolute crop The netting experiment was conducted at Hawassa and failure have been reported from various places in Ethiopia Meki. Hawassa is located between 7° 3’ latitude north and 38° [9,10]. Relative importance of viruses on pepper is quite er- 28’ longitude east at altitude of 1680 meter above sea lev- ratic across regions, where a few viruses are common to a el. This area is characterized by dry sub humid climate; it has particular region. Ethiopian pepper mottle virus (EPMV), a monthly mean minimum and maximum temperature of 10.4 potyvirus occurring in diverse or single infection, is the most °C and 27.5 °C, respectively and annual rain fall of 900-1300 significant virus in the rift valley and southern parts of Ethio- mm. Meki is located between 7°58’ latitude north and 38°43’ pia [7,9,10]. Local and regularly grown varieties such as ‘Mar- longitude east at altitude of 1636 meter above sea level. It is kofana’ are highly susceptible to EPMV and aphids which help has annual rain fall of 500-1159 mm and minimum and maxi- as vector to spread this disease [8,11]. mum temperature of 12 °C and 27.5 °C respectively. Crops and weeds in and around fields may affect the spe- Planting and treatment description cies diversity of vectors and are often potential sources of virus inoculum Tameru, et al. and Atsebeha, et al. [10,11] found Seedlings of the pepper variety Marekofana which highly several cultivated crops and volunteer plants that influenced is susceptible to EPMV were raised under a protective cover the species composition of aphids present on pepper farms. and sprayed with the systemic insecticide dimethoate (1 liter/ The migratory habits of aphids make them important vectors hectar) weekly to restrict aphids that are vector for EPMV. of plant viruses. Peak aphid flights and the presence of known Pepper seedlings were transplanted to the Hawassa universi- vectors are often associated with rapid spread of viruses in a ty experimental field and commercial farm field at Meki, when they reached a two leaf growth stages. Experimental plots particular area. In some case virus incidences are correlated had a size of 2 m × 2 m each and the spacing between plant with high numbers of inefficient vectors when the numbers of and rows were 0.3 m × 0.5 m respectively. The plots and block efficient vectors were low[11 ,12]. were spaced one meter apart. A plot contained four rows and The epidemiology of viruses differ along with localities, each row had six plants, as a result, there were 24 plants per time and a factor of local source of inoculum, vector complex plot. The experiment was laid out in randomized complete involved and how the pretenses of vectors are harmonized block design (RCBD) with three replications consisting of the with the phenology of the crop [12]. So understanding the following Treatments: T1: No net barrier (control), T2: Pepper epidemiology of aphid-borne viruses is very essential for the covered with net for up to 20 days after transplanting (DAT), development of appropriate management strategies. Barrier T3: Pepper covered with net for up to 40 DAT, T4: Pepper cov- crops, mulches and nets are used to decrease virus infection ered with net for up to 60 DAT, T5: Pepper covered with net and vector infestation in several non-persistently transmitted for up to 80 DAT or until flowering, T6: pepper covered with

Figure 1: Pepper growing under netting.

Dida et al. J Plant Pathol Res 2020, 2(1):6-12 Open Access | Page 7 | Citation: Dida K, Chala A, Azerefegne F (2020) Effect of Netting Duration on Ethiopian Pepper Mottle Virus (EPMV) Infection and Aphid Infestation of Hot Pepper (Capsicum annuum L.) in Central Rift Valley Region of Ethiopia. J Plant Pathol Res 2(1):6-12 net until harvesting, T7: Weekly spraying of dimethoate 40% Marketable yield and unmarketable yield EC (1000 ml/ha), A contact insecticide, applied at seven days Pepper pods were harvested from the inner two rows of interval. Covering of pepper plants was made using a stan- each plot, and the pods were sorted into marketable and un- dard nylon net capable of blocking vector infestations (Figure marketable pods based on the presence or absence of green 1). The pepper was grown under irrigation. The recommend- mottling, swelling, color, and shape deformation. Weights of ed rate of DAP (200 kg/ha) and half of the recommended rate marketable, unmarketable, and total fruit were measured. of urea (100 kg/ha) fertilizers were applied in bands at the time of transplanting. The remaining half rate of urea was ap- Marketable yield (q/ha): The marketable yield of eight plied during active stage of vegetative growth [14]. All other sample plants per plot was determined at harvesting by sort- recommended cultural practices were performed uniformly ing fruits according to color, shape, shininess, firmness, and to all plots as per the recommendation. size of the fruits. After separation, the weight of marketable fruits were recorded and converted to q/ha. Data Collection Unmarketable yield (q/ha): The yield which was obtained Monitoring of aphid populations in experimen- by sorting the diseased, discolored, shrunken, shaped and small size, totally unnecessary pod separated from market- tal field able pods were recorded at harvest and converted to q/ha. Aphids were monitored by using Yellow Water Traps Total yield (q/ha): Weight of total marketable and un- (YWT) that was made from yellow plastic container with size marketable fruits harvested from each sample plants were of 10 × 35 × 20 cm (Figure 2). One YWT was placed in the recorded and summed up to estimate yield per hectare. middle of each plot one week after transplanting of pepper plants. The traps were filled with water up to small outlets be- Data Analysis low the rim. The heights of the traps were adjusted according Data on aphid populations, viral incidence, and yield were to the crop canopy. Five milliliter of formaldehyde was added subjected to analysis of variance (ANOVA) using General Lin- in the water of each trap to keep the aphids intact and pre- ear Model (GLM) procedures of SAS version 9.00 [16]. When- vent birds from drinking the water. Every week, the solution ever treatment differences were significant, the differences in YWT was changed and trapped aphids were collected un- among treatment means were compared using LSD test at til the pepper crop fully matures. The collected aphids were 5% level of significance. Correlation analysis was carried out by using proccorr procedure of simple Pearson correlation to counted according to date of collection and treatments. The assess the relationship between aphid populations, disease data was summarized to investigate the population of aphids incidence and yield. in relation to the crop phenology. Result and Discussions Incidence of Ethiopian pepper mottle virus (EPMV) Symptoms of Ethiopian pepper mottle virus characteris- Starting 20 days after transplanting, all pepper plants in tics including severe reduction of leaf size, curling, crinkling each plot were visually assessed for the incidence of EPMV of interveinal areas, interveinal and marginal chlorosis, occa- infection caused by natural infestation special aphid’s infes- sional development of venations, shortening of internodes, tation. Well established symptoms based evaluation method stunting or dwarfing, development of small branches, and for EPMV was used for rating of the incidences [8,15]. Ethio- bright yellow spot on leaves, mottle and reduced fruiting pia pepper mottle virus incidence on each experimental treat- were observed in pepper experimental fields (Figure 3). ment was recorded by counting number of diseased plants Incidence of Ethiopian pepper mottle virus and calculating as the proportion of the diseased plant over the total number of stand count per treatment. Analysis of variance indicated highly significant differ-

Figure 2: Aphid monitoring using yellow water trap.

Dida et al. J Plant Pathol Res 2020, 2(1):6-12 Open Access | Page 8 | Citation: Dida K, Chala A, Azerefegne F (2020) Effect of Netting Duration on Ethiopian Pepper Mottle Virus (EPMV) Infection and Aphid Infestation of Hot Pepper (Capsicum annuum L.) in Central Rift Valley Region of Ethiopia. J Plant Pathol Res 2(1):6-12

Figure 3: Pepper plants showing EPMV disease symptom.

Table 1: Effect of nets on aphids per plant, average disease incidence and final disease incidence.

Treatment Aphids per plants ± SE Average disease incidence ± SE Final disease incidence ± SE Hawassa Meki Hawassa Meki Hawassa Meki Uncovered 40.50 ± 1.72a 45.21 ± 0.91a 57.50 ± 1.30a 63.12 ± 1.19a 81.25 ± 2.60a 87.50 ± 0.50a Netting for up to 20 days 27.75 ± 1.97b 39.37 ± 0.34ab 43.75 ± 1.25ab 52.50 ± 1.04b 71.87 ± 2.12ab 78.12 ± 0.13ab Netting for up to 40 days 17.93 ± 0.87c 25.90 ± 2.06bc 34.97 ± 1.39bc 42.50 ± 1.02cd 51.37 ± 1.05cd 65.62 ± 1.10cd Netting for up to 60 days 17.37 ± 1.34c 21.56 ± 0.52bc 29.87 ± 1.83bc 38.75 ± 1.25de 40.62 ± 1.12de 59.37 ± 2.12d Netting for up to 80 days 13.06 ± 0.65c 18.31 ± 1.03c 24.37 ± 0.62c 35.00 ± 1.04de 37.50 ± 0.24de 43.75 ± 1.60e Netting until harvesting 10.50 ± 0.47c 14.90 ± 1.27c 22.50 ± 0.33c 32.50 ± 1.06e 34.37 ± 1.13e 40.62 ± 1.12e Spraying with insecticide 30.81 ± 0.19b 37.37 ± 2.71ab 48.12 ± 1.60ab 49.37 ± 1.19bc 66.25 ± 2.60bc 75.00 ± 0.25bc LSD (0.05) 8.87 17.84 18.64 9.11 14.92 12.20 CV (%) 15.92 26.37 21.39 8.69 11.66 8.12

Where, CV: Coefficient of variation; LSD: Least significant difference; SE: Standard error. Means in a column followed by the same letter are not significantly different at p < 0.05, whereas the means indicated by different letters shows significantly different. ence in virus incidence across treatments at both locations. Meki. The results are consistent with the finding of DiFonzo, The lowest EPMV incidence (22.5% at Hawassa and 32.5% et al. [12] who reported rapid spreading of viruses in partic- at Meki) was recorded from the pepper plants covered by ular area associated with the presence of vectors and hosts. net until harvesting (Table 1). On the other hand, the high- Atsebeha, et al. [11] also reported increasing of virus with a est mean EPMV incidence (57.5% in Hawassa and 63.12% in large diversity of crop species cultivated and weed species in Meki) was recorded from uncovered plots. Therefore, netting and around field. Similarly, Nault, et al. [18] reported the in- until harvesting was considered the most effective in reduc- fection of Cucumber Mosaic virus (CMV) in Alfalfa was greatly ing viral incidence. In a previous work, Olobashola, et al. [17] associated with dispersal of aphids from nearby Snap Beans. reported aluminum mulching as effective measure in reducing virus incidence. Aphid’s population per plant Overall disease incidence was high in Meki as compared Aphids were more abundant at Meki as compared to Ha- to Hawassa. This might be due to the presence of several wassa. This might due to the presence of many hosts in and hosts for the vectors in and around the experimental field in around pepper fields and environmental condition in Meki

Dida et al. J Plant Pathol Res 2020, 2(1):6-12 Open Access | Page 9 | Citation: Dida K, Chala A, Azerefegne F (2020) Effect of Netting Duration on Ethiopian Pepper Mottle Virus (EPMV) Infection and Aphid Infestation of Hot Pepper (Capsicum annuum L.) in Central Rift Valley Region of Ethiopia. J Plant Pathol Res 2(1):6-12 area. This result agrees with DiFonzo, et al. [12] who report- plots covered by net for up to 20 days after transplanting at ed the positive role of several cultivated crops and volunteer both locations. Variation was might be due to reduction of plants in increasing the population of aphids in potato farms virus infection and vectors infestation. This finding agree with in the same region. Similarly, Atsebeha, et al. [11] reported Fajinmi and Odebode, et al. [19] who indicated that increased that population of aphid species was high in the presence of in fruit yield and quality was achieved with a reduction of dis- large diversity of crop species cultivated. eased plant by controlling of pepper veinal mottle virus. The mean number of aphids per plant across treatments As compared to control plots, marketable yield was in- at both locations was significantly different. Plots covered creased by 49% and 48% at Meki, 55% and 51% at Hawassa by net until harvesting and up to 80 days after transplanting when plants were covered by net until harvesting and cov- were consistently significantly different from plots of other ered by net for up to 80 days after transplanting, respectively treatments in reducing the aphid population regardless of (Table 2). Avilla, et al. [20] also indicated 20 to 80% increase the location. On the other hand, the significance reduction in in marketable yield when plants were infected by potyvirus at aphid population was varied depending on the location when latter growth stage. plots were covered with nets only up to 60 days after trans- Unmarketable yield: The result revealed that netting du- planting (Table 1). ration had a significant (P < 0.01) effect on the unmarketable The highest mean number of aphids per plants (40.5 in yield. Control plots were significantly different from plots cov- Hawassa and 45.21 in Meki) was recorded from control plots ered by net for up to 40 days and longer at Hawassa while it while the lowest mean of aphids per plants (10.5 in Hawassa was significantly different from plots covered by net for up to and 14.9 in Meki) was recorded from plots covered by net 60 days and more at Meki (Table 2). The highest mean unmar- until harvesting. As compared to the control plots, the mean ketable yield (1.53 q/ha in Meki and 1.08 q/ha in Hawassa) number of aphids per plant was reduced by 74% at Hawas- was recorded from control plots. On the other hand, the low- sa and 67% at Meki, when plots were covered by net until est mean unmarketable yield (0.27 q/ha in Meki and 0.11 q/ harvesting. On other hand, covering plots by net for up to 80 ha in Hawassa) was recorded from plots covered by nets until days after transplanting has reduced mean number of aphids harvesting and covered by net for up to 80 days after trans- per plant by 67.8% and 40.5% at Hawassa and Meki respec- planting, respectively (Table 2). Meyers, et al. [21] reported tively, as compared to the unprotected plots (Table 1). 50-60% yield reduction of pepper plants due to the infection of potyvirus. Effect of netting duration on yield In this study it was observed that unmarketable yield Marketable yield: Netting duration had a highly signifi- decreased with increasing in net cover duration. This might cant effect on marketable yield of pepper at both locations. be due to nets protecting aphids infestation at early growth Plots covered by net until harvesting and up to 80 days were stage and physiological disorders (bleaching) during the fruit significantly different in terms of marketable yield from plots set or the climatic conditions of the growing environment. without netting, covered by net for up to 20 days and weekly As compared to control plots, plots covering plants by nets spraying with insecticide at both locations (Table 2). Highest up to 80 days after transplanting or until harvesting reduced mean marketable yield was harvested from plots covered by unmarketable yields by 80-89% at Hawassa and 75-82% at net until harvesting and up to 80 days followed by netting up Meki (Table 2). This finding was agreement with Fuchs and to 60 days after transplanting. On the other hand, the lowest Minzenmayer, et al. [22] who reported greater than 25% re- mean marketable yield was harvested from control plots and duction in cotton fruit yield when crops with higher incidence

Table 2: Effect of netting duration on marketable, unmarketable and total yield.

Treatments Marketable yield (q/ha) ± SE Unmarketable yield (q/ha) ± SE Total yield (q/ha) ± SE Hawassa Meki Hawassa Meki Hawassa Meki Uncovered 11.45 ± 0.80d 10.33 ± 0.96c 1.08 ± 0.27a 1.53 ± 0.24a 12.53 ± 0.77c 11.86 ± 0.68c Netting for up to 20 days 11.99 ± 0.49cd 10.75 ± 2.07bc 1.06 ± 0.18a 1.26 ± 0.18ab 13.05 ± 0.40c 12.01 ± 0.89c Netting for up to 40 days 16.10 ± 0.69abc 13.10 ± 0.87ab 0.39 ± 0.16ab 1.16 ± 0.19abc 16.50 ± 0.82abc 14.26 ± 0.24abc Netting for up to 60 days 16.51 ± 1.61ab 14.26 ± 1.93a 0.23 ± 0.06b 0.64 ± 0.24bcd 16.74 ± 1.57abc 14.91 ± 0.99ab Netting for up to 80 days 17.30 ± 1.10a 15.33 ± 1.74a 0.11 ± 0.03b 0.37 ± 0.14cd 17.42 ± 1.08ab 15.71 ± 0.74a Netting until harvesting 17.75 ± 0.92a 15.45 ± 2.03a 0.21 ± 0.05b 0.27 ± 0.11d 17.96 ± 1.90a 15.72 ± 0.94a Spraying with insecticide 12.14 ± 0.56bcd 11.48 ± 1.05bc 0.97 ± 0.02a 1.41 ± 0.20ab 13.12 ± 0.53bc 12.90 ± 0.66bc LSD (0.05) 4.38 2.73 0.71 0.88 4.29 2.68 CV (%) 12.7 9.03 52.92 39.54 11.99 8.24

Dida et al. J Plant Pathol Res 2020, 2(1):6-12 Open Access | Page 10 | Citation: Dida K, Chala A, Azerefegne F (2020) Effect of Netting Duration on Ethiopian Pepper Mottle Virus (EPMV) Infection and Aphid Infestation of Hot Pepper (Capsicum annuum L.) in Central Rift Valley Region of Ethiopia. J Plant Pathol Res 2(1):6-12 of potyvirus. Similarly, Mukasa, et al. [23] reported up to 98% In general, there was positive and highly significant (p decrease in yield when sweet potato plants were infected by < 0.001) correlation between virus incidence, aphids popu- sweet potato feathery mottle virus at latter growth stages lation and unmarketable yield. This finding is in agreement than early growth stages. with Fajinmi, et al. [25] who reported that aphids’ distribution within a particular area has a significant contribution in trans- Total yield: Netting duration had a highly significant ef- mitting viral diseases that subsequently lead to yield losses. fect on total yield of pepper at both locations. Generally, the Marketable yield and total yield were negatively correlated highest mean total yield was harvested from plots covered by with virus incidence and aphids population at both locations net until harvesting and up to 80 days followed by covered (Table 3 and Table 4). Increasing disease incidences and vec- by net for up to 60 days while the lowest total yield was har- tors can cause significant reduction in the yields. Fajinmi and vested from plots without netting and covered by net for up Odebode, et al. [19] reported that the yield of pepper was to 20 days after transplanting at both locations (Table 2). This negatively correlated with pepper mottle virus and vectors. result agrees with Agrios and Walker, et al. [24] who reported increased in growth and yield when pepper plants were in- Conclusion fected at latter growth stage. Pepper is an important cash and spice crop in Ethiopia. It As compared to control plants (no netting), pepper plants is widely cultivated in some part of Ethiopia especially in the from plots covered by net until harvesting and up to 80 days rift valley. However, the production is affected by abiotic and after transplanting gave 39-43% and 32% more yield at Ha- biotic factors. Among biotic factors, viral disease transmitted wassa and Meki, respectively (Table 2). Tameru, et al. [10] by vectors is one of the main problem productions of pepper also reported greater than 90% yield loss and complete pep- in the central rift valley of Ethiopia. per plants failure in Ethiopia by potyvirus genus special Ethi- In Ethiopia, there is a gap in managing viral diseases of opian pepper mottle virus and potato virus Avilla, et al. [20] crop plants (including pepper) in a way that increases the found similar effects of virus on total weight and marketable quantitative and qualitative yield of peppers. Hence, the pres- weight of fruit produced by pepper plants infected at different study aims to contribute towards effective and sustain- ent stage of development. able management of pepper virus for improved yields. The Correlation between disease, vectors and yield experiment determined the role of netting cover in protecting pepper plants from pepper mottle virus and their vectors. Correlation analysis among disease and yields revealed Overall, significant increase in virus infection and aphids in- the negative impacts of virus on pepper quantitative and festation was recorded at both experimental fields (Hawassa qualitative yield except unmarketable yield which was posi- and Meki), when pepper plants grew without netting. This tively influenced by disease and vectors at both locations (Ta- was followed by significant reduction in growth parameters ble 3 and Table 4). This result is in agreement with Tameru, (plant height, number of branches per plant and leaf canopy et al. [8] who reported reduction in pepper pod yield due to cover) and yield, especially marketable yield. The effect was potyvirus. comparable to weekly spraying with insecticide, suggesting

Table 3: Correlation among disease, vectors, growth parameter and yield at Meki.

BN PH LCC POD MY UMY TY INC APH MY 0.5599** 0.6665*** 0.7079*** 0.6064*** 1 UMY - 0.5215** - 0.6794*** - 0.5536** - 0.7220*** - 0.7219*** 1 TY 0.5152** 0.5965*** 0.6817*** 0.5130** 0.9801*** - 0.5704** 1 INC - 0.5500** - 0.7530*** - 0.8771*** - 0.7142*** - 0.7957*** 0.6832*** - 0.7487*** 1 APH - 0.4758* - 0.7772*** - 0.7014*** - 0.6046*** - 0.5595** 0.6880*** - 0.4670* 0.5241*** 1

Where, * = p < 0.05, ** = p < 0.01 and *** = p < 0.0001 MY: Marketable yield; UMY: Unmarketable yield; TY: Total yield; INC: Viral incidence; APH: Aphids population per plant.

Table 4: Correlation among disease, vectors, growth parameter and yield at Hawassa.

BN PH LDC POD MY UMY TY INC APH MY 0.6877*** 0.6456** 0.4216* 0.5524** 1 UMY - 0.6853*** - 0.6406** - 0.4565* - 0.6127** - 0.7553*** 1 TY 0.6538** 0.6143** 0.3945* 0.5142** 0.9933*** - 0.6746*** 1 INC - 0.7332*** - 0.7421*** - 0.4626* - 0.5125** - 0.7283*** 0.5941*** - 0.7157*** 1 APH - 0.7416*** - 0.7757*** - 0.5721** - 0.5986** - 0.7686*** 0.7738*** - 0.7294*** 0.8365*** 1

Where * = p < 0.05, ** = p < 0.01 and *** = p < 0.001 MY: Marketable yield; UMY: Mnmarketable yield, TY: Total yield; INC: Viral incidence; APH: Aphids population per plant.

Dida et al. J Plant Pathol Res 2020, 2(1):6-12 Open Access | Page 11 | Citation: Dida K, Chala A, Azerefegne F (2020) Effect of Netting Duration on Ethiopian Pepper Mottle Virus (EPMV) Infection and Aphid Infestation of Hot Pepper (Capsicum annuum L.) in Central Rift Valley Region of Ethiopia. J Plant Pathol Res 2(1):6-12 the inefficiency of the applied insecticide. On the other hand, abundance of aphid vectors of Potato virus Y in the Red River net cover up to 80 days or more significantly reduced pepper Valley of Minnesota and North Dakota. Journal of Economic En- viruses and their vectors while significantly improving yield tomology 90: 824-831. and yield component. 13. Fajinmi AA, Fajinmi OB (2010) Incidence of okra mosaic virus at different growth stages of Okra plants (Abelmoschusesculen- Acknowledgment tusL. Moench) under tropical condition. Journal of General and We thankfully acknowledge the financial grant from IPM Molecular Virology 2: 28-31. 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DOI: 10.36959/394/619

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